I gave a shot to brewing and since there were not pecise documentation (only the genral guiddelines and ideas) i tried experimenting.
On my "control" barrel i gave maximum quantity possible for each ingredients (until the barrel was not in capacity to eceive those items anymore), the barrel was in chunks loaded by chunk loader on a local server so it could ferment while i'm away by letting the server run.
I kept track of time with Computercraft , so with the Computercraft system is started the experiment on day 131 and opened the

Steps To Reproduce

Place barrel, load it with full capacity for each ingredients, place a chunk loader to make it tick while you're away and then wait for more than 40 days.
Could make a control expeeriment with the same process but waiting 80 days to check.

Additional Information

I recall there was an incident with the chunk loader, i've put my computer in sleep mode the first night (real time) and when i came back to play the next day the chunk loader was sort of corrupted (and an eror was logged into the server console), its texture was the one of the missing texture and some lightning bugs were present in the chunks afffected by the chunk loader.
So this must have happened around day 140 in game.